[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Message-ID: <Pine.LNX.4.44L0.0901151010110.2490-100000@iolanthe.rowland.org>
Date: Thu, 15 Jan 2009 10:13:37 -0500 (EST)
From: Alan Stern <stern@...land.harvard.edu>
To: ozan@...dus.org.tr, Iwo Mergler <iwo@...l-direct.com.au>
cc: Kernel development list <linux-kernel@...r.kernel.org>,
USB list <linux-usb@...r.kernel.org>
Subject: Re: A really interesting mass-storage BUG introduced after 2.6.18
On Thu, 15 Jan 2009, Iwo Mergler wrote:
> >
> > This shows the computer sending a TEST UNIT READY command to the drive,
> > and the drive reporting Unit Attention: Media not present. So of
> > course Linux believes there is no media loaded in the drive and doesn't
> > try to read the partition table or anything else.
> >
> > Presumably if the drive is plugged in during bootup then the BIOS does
> > something to make this error status go away. It's hard to guess what
> > that would be, however.
> >
>
> It could be a matter of timing. Some badly designed USB devices have a
> dead time between power-up and being ready, but show up on the bus as
> if they where. The "Media not present" thing could be a symptom of this.
Good point.
> To verify it, try inserting the device slowly. The power contacts in
> the USB connector are longer than the data contacts and the device gets
> more time to boot.
Another timing-sensitive values you can set is the delay_use module
parameter for usb-storage. It defaults to 5 seconds but perhaps you
need a longer delay.
Alan Stern
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists